Current switching arrangement to cutout the defective gas lamp upon failure



Oct. 3, 1967 PETERSON ETAL CURRENT SWITC HING ARRANGEMENT TO CUTOUT TH DEFECTIVE GAS LAMP UPON FAILURE Filed Oct. 23, 1965 no V. AC.

2 no V.A.C. i n 5a 36 2 76 LoJJ 5 5 INVENTORS. 6 j /0 Donal/an fPetersa/r ""033: p j r lg. a smusse a arr/s 5 /3 J A 26 38 I United States Patent O H p 3,345,538 CURRENT SWiTCHlNG ARRANGEMENT T CUTOUT THE DEFECTIVE GAS LAMP UPON FAILURE Donovan F. Peterson, Elm Grove, Clarence E. Rasmussen,

Whitewater, and Roy J. T. Harris, Milton, Wis., assignors to U.S. Automatics Corporation, Pewaulcee, Wis., a corporation of Delaware Filed Oct. 23, 1965, Ser. No. 503,026 7 Claims. (Cl. 315-125) ABSTRACT OF THE DIStCLOSURE When one of two electrical devices being supplied with inductively restricted current flow fails and becomes nonconductive the restricted current flow is re-established inductively for the other device by shunting the failing device with connection which include a switch connected between the flow restricting element and said one of said devices and shunting the latter.

The present invention relates generally to two or more interrelated electrical devices operated in connection with a common current responsive impedance component, one device involving wide swings in current and magnetic flux between running and failure, and the other requiring initiation or continuing operation with a constant current factor throughout its use particularly in event of the failure of the first device.

The invention is also characterized by continuously supplying current to an electrical hygienic instrument and in the same current bearing circuit simultaneously operating an electrical hygienic protection device involving substantial changes in current or magnetic flux upon failure thereof.

By way of example vapor lamps producing ultraviolet energy concentrations can be employed for health or safety reasons with various electrical current consuming devices such as hair clippers, shavers, toothbrushes, scalp massagers and nail files, particularly those driven with a rechargeable battery. Ultraviolet-energy can be used directly for hygienic purposes or fluoresced for illumination along with the use or storage of the electrically driven appliances requiring sterilization or illumination.

More particularly, in the operation of a mercury vapor lamp characterized by radiant energy emission from an ionized gas that is carrying current betweenelectrodes with a negative resistance characteristic, free electrons must be introduced to start ionization of the gas. Accordingly, the initial internal resistance in the lamp to the flow of current is quite high but when the arc is established either by heat or high electrical potential the internal resistance dropsimmediately as well as the voltage differential across the lamp. Therefore, once the arc is established a current flow impeding device is required in the electric circuit to prevent damage to the lamp.

Such a device is generally termed a ballast and may constitute a resistance in direct current applications or a capacitance for high frequency currents, or preferably an inductive reactance where standard alternating currents are involved. If the running voltage is high enough to start the lamp, a simple choke can be used as a ballast, but when a higher starting voltage is required, the ballast usually is an auto-transformer with or without capacitors. Each size of lamp requires a ballast designed to match the requirements of the lamp, its starting voltage current, and its sustaining current.

With the circuits prevalent today, the ballasts include ferrous cores having air gaps and suitable windings to provide a satiable reactance desired for throttling current flow in circuits. For instance, in rapid start circuits the ballast includes choke filament windings which provide the required voltage and current for continuous heating. In the present embodiment of the invention a single winding is used to both heat the filament and provide the current desired for sustaining ionization of the gas, same being simple to demonstrate and understand and being representative of ballast relationships contemplated by the invention. Filament energization is a substantially constant load while the choke winding experiences a wide fluctuation in both current and voltage drops and in resulting magnetic flux in all ballasts used whether the starting circuits are rated preheat, instant start or rapid start. The current, differential voltage use and magnetic flux rise with ignition and drop with lamp failure.

Lamps are the components which generally fail and to avoid the lOSs of the results of the lamp function, where important or critical, two lamps burning simultaneously have heretofore conventionally been provided because they are not likely to fail at the same time. This involves extra expense generally including a second ballast and extra current. It is desirable to save the cost of the additional ballast and also desirable to power other electrical devices in series with a single ballast because of its current flow throttling elfect. However, with a lamp failure, the current under that condition may fall too low for operation of another electrical device.

A primary object of this invention is to provide a standby arrangement which automatically continues the current throttling capability of a vapor lamp ballast for operation of other devices in event of the lamp failure.

A further object of the invention is to provide a ballast of reduced impedance which along with an additional serially connected device will provide a vapor lamp with the proper ballast or impedances for proper functioning without dropping the load in event of lamp failure.

Another object resides in a vapor lamp ballast construction in which another electrical device can be powered therefrom upon failure of the vapor lamp, such other device including an alternate or standby vapor lamp or other current consuming device either as a continuing or initiating function.

The invention is also characterized by a warning function of a primary vapor lamp failure which carries on other current consuming functions and can be reset when the failure is corrected.

These being among the objects of the invention other and further objects will appear from the drawing and description relating thereto showing two embodiments in which:

FIG. 1 is a schematic diagram of the circuit and components embodying the invention as related to solid state switching elements;

FIG. 2 is a similar view of another embodiment of the invention;

FIG. 3 is a schematic diagrammatical view of another embodiment of the invention related to operation of mechanical switching elements; and

FIG. 4 is a view similar to FIG. 3 in which vapor lamps are used in service and standby reserve capacities.

FIG 5 is a view similar to FIG. 3 in which a normally open switch shunts the lamp to energize a load when the lamp fails.

The vapor lamp employed in describing the invention is a rapid-start lamp 10 having a single filament 12 in the lamp circuit with spaced electrodes 14 and 16 one at each end thereof. The firing voltage is approximately thirty volts and as soon as the filament begins to release ions the lamp arcs between the electrodes shorting out the filament and although the voltage potentially can approach zero, a ballast winding 18 is provided to maintain J a sustaining voltage of approximately volts thereacross at 300-600 milliamperes.

The lamp 10, which serves as a germicidal lamp for a device such as hair clippers 22 operated by a motor 24 powered with a battery 26 energized by a charger 28, is shielded from eyesight by a fluorescing shield 30 which shines when the lamp is emitting to indicate operativeness.

The lamp 10 is shunted by a solid state device referred to as a symmetrical diode as represented by two trigger diodes 32 reversely connected in parallel to conduct alternating current.

The diode switch 32 has a breakdown voltage above the starting voltage of the lamp, it being anywhere between lamp firing voltage and the line voltage of 110 V. AC. The conduction voltage is as low as 1 volt, and in event the lamp 10 burns out the voltage of 10 volts across the lamp terminals and the switch 32 will rise towards line potential with no current flowing through the ballast winding 18. This rise breaks down the switch thereby maintaining current flow through the winding 18 comparable to the sustaining current. Thus, a voltage sensitive solid state switch is connected across a vapor lamp which automatically acts as an automatic circuit maker when the lamp burns out to maintain current through the ballast for other associated purposes.

For such purposes, it will be observed that the ballast winding 18 is associated with an iron core 34 and a second winding 36 thereon. The second winding 36 energized by transformer action of a current flowing through the ballast Winding 18 powers the charger 28 through a diode 38 with half wave rectified current. The lagging power factor angle of the ballast keeps the switch 32 conducting for about 95% of the cycle so long as its breakdown voltage resides somewhere between the lamp firing voltage and the line voltage.

Accordingly, the charging of the battery will be continuous between detached uses of the battery and motor 24 from the lamp ballast irrespective of the operation or failure of the lamp, yet a failure indication will alert the user to replace the lamp without interrupting or jeopardizing regular use of the hygienic device.

In FIG. 2 a simpler device is shown, although more expensive due to the cost of a transformer and ballast as distinguished from an auto-transformer type ballast. Herein a transformer 40 is used which has a tapped 42 secondary coil 44. The battery 26 is continuously charged by a low voltage section 46 of the secondary coil 44 while the firing voltage and sustaining current for the lamp 10 is supplied by the main portion 48 of the secondary coil.

The flow of current through the lamp 10 is controlled by a Ballister regulator 49, a trademark of US. Automatics Corporation, which can be characterized as a thermistor With a positive coefficient in which the resistance effect varies directly and proportional to the impressed current, which in the embodiment illustrated provides in connection with the lamp 10 a voltage drop of 10 volts across it at 300 milliamperes.

Referring now to FIG. 3, a rapid starting circuit is shown for the gaseous discharge lamp 10 as connected across an auto-transformer 50 having a winding portion 52 and an inductive reactance winding portion 54 disposed on the bight of a C shaped ferrous core 56. When the current is turned on by closing switch 58, current induced in coils 52 and 54 heat the filament 12 in the lamp to initiate electron flow whereupon the internal resistance in the lamp drops permitting serial current flow from one electrode 14 to the other electrode 16 through the envelope as throttled by the inductive reactance in the ballast.

In cooperation with the air gap 60 of the core 56 a single-pole, single-throw switch 62 is illustrated having a ferrous armature 62 that spans the air gap as urged to its closed position by spring 66 away from the pole pieces 68 defining the gap. A manual reset button is shown at 70 to move the switch to its open position by moving the armature towards the pole pieces. Insulating members 72 are provided which space at least one armature end from its adjacent pole piece to preserve the air gap.

When the switch 58 is closed the armature of switch 62 will be away from the pole pieces, closing the switch 62 in a manner shunting the heater 12 of the lamp 10 but inducing current to flow through the load. However, when the reset button is pressed, the switch 62 is opened and the heater 12 is immediately heated and the lamp 10 is ignited. When ignited its internal resistance drops, and flow therethrough is limited by coils 52 and 54 and the Load is powered in series therewith. The lamp is left on for long periods of time either for dark stairways or germicidal purposes, depending on the nature of the lamp.

It will be seen that a load, within the capabilities of the ballast is constantly energized in either position of the switch if the lamp is operating because the low resistance thereof provides adequate current and with the armature moved towards the pole pieces, the magnetic flux of the core will hold it there as long as there is low resistance through the lamp.

However, if the lamp fails, the electron emission ceases, and the resistance across the lamp greatly increases, inhibiting the current flowing through the ballast and load. This results in a drop in the magnetic flux developed in the core 56 thereby releasing the switch armature 62 to the effect of the spring 66 working in the direction of the arrow whereupon the non-conducting lamp is shunted and adequate current through the load is re-established with closure of the switch. The load continues to be energized until the lamp is replaced whereupon the reset procedure described is re-enacted.

With reference to FIG. 4, an arrangement is shown in which current alternatively is maintained by switching between two vapor lamps 10, one 10a working as the service lamp and the other lamp 10b as a standby reserve lamp. The switch 62a in this construction is a single-pole double throw switch as urged diagrammatically by the spring 66 in the direction of the arrow which when pressed towards the pole ends after the switch 58 is closed, is magnetically held to pass current through lamp 10a. When lamp 10a burns out, the windings 52 and 54 are momentarily de-energized, dropping the flux in the core, releasing te armature to its resting position shown to energize lamp 1% and maintain current flow through the load.

In FIG. 5 a modification of the circuit of FIG. 3 is shown in which the load is connected serially with the lamp 10 and the inductive ballast 54 when the lamp is energized, and is connected serially with the inductive ballast 54 when magnetic flux induced by current fiow through the lamp 10 is stopped by lamp failure. In either event operation of the load is continuous when handled as already described in connection with FIG. 3.

In the embodiments of FIGS. 1 and 3 an auxiliary or standby lamp can also be provided by connecting it in series with the switch. In such event the firing voltage of the primary lamp being less than the breakdown voltage of the diode switch 32 in FIG. 1 the burning lamp will strike an arc. Then when the primary lamp fails, the voltage across the serial switch and auxiliary lamp rises until the diode switch breaks down, whereupon the auxiliary lamp strikes an arc and the switch continues to conduct. In such event with FIG. 3 both lamps might arc but reset of the switch to its magnetically influenced position would deactivate the auxiliary lamp until the primary lamp failed.

Having thus described several embodiments of the invention, it will be appreciated how the objects are attained and how various and further embodiments can be provided without departing from the spirit of this invention, the scope of which is commensurate with the appended claims.

What is claimed is:

1. In combination, a vapor lamp producing ultraviolet energy shielded from eyesight, an inductive ballast having a first winding electrically connected in series with the lamp and a second winding inductively coupled thereto, a normally non-conducting switch means shunting said lamp responsive to electrical current changes in said first winding for conducting current through said first winding upon lamp failure, and an electrical device connected in series with said second winding.

2. In combination, a vapor lamp producing ultraviolet energy, an electrical device associated therewith for continuous operation, an inductive ballast electrically connected in series with the lamp and said electrical device, a switch shunting said lamp normally held open by magnetic flux induced by current flowing through the lamp and connecting said electrical device in series with said ballast when closed, and means responsive to a drop in magnetic flux in said ballast when said lamp fails for closing said switch to activate said electrical device.

3. In combination, a negative resistance characteristic vapor lamp producing ultraviolet energy shielded from eyesight during operation, an electrical device associated therewith for continuous operation, an inductive ballast electrically connected in series with the lamp, an inductively coupled winding associated with said ballast connected in series with said electrical device, means for shunting said lamp and connected in series with said ballast for sustaining conduction of current through said ballast for continued operation of said electrical device upon failure of the vapor lamp.

4. In combination, a vapor lamp producing ultraviolet energy and having a negative resistance characteristic, a ballast connected in series with the lamp for controlling the flow of current through the lamp during its operation, a switch connected in series with said ballast and in parallel with said lamp including a solid state diode having a breakdown voltage above the firing voltage of the vapor lamp, a winding inductively coupled to said ballast, and a current consuming device connected in series with said winding for continuous operation from electrical current through said winding.

5. In combination, a vapor lamp producing ultraviolet energy for germicidal purposes and shielded from eyesight and having a negative resistance characteristic, a ballast having a winding connected in series with the lamp for controlling the flow of current through the lamp during its operation, a switch connected in series with said winding and in parallel with said lamp including a solid state normally non-conducting diode having a breakdown voltage above the firing voltage of the vapor lamp, a second winding inductively coupled with the first winding and a current consuming device connected in series with the second winding for continuous operation for powering a hygienic instrument exposed to said ultraviolet energy "for personal use by an individual.

6. In combination, a lamp radiating germicidal energy protectively shielded from eyesight, an inductively coupled winding connected in series with the lamp during its operation, a normally non-conducting switch means connected in series with said winding and in parallel with said lamp, said switch means including a solid state junction having a conducting voltage level above the voltage drop across said lamp and a current consuming device connected in series with said winding.

7. The combination called for in claim 3 in which said means includes a magnetically responsive switch inductively controlled by current passing through said inductive ballast.

References Cited UNITED STATES PATENTS 1,960,408 5/1934 Brach 315 2,278,061 3/1942 Dalkowitz 2402 2,461,265 2/1949 Gates 315-276 JAMES W. LAWRENCE, Primary Examiner. C. R. CAMPBELL, Assistant Examiner. 

1. IN COMBINATION, A VAPOR LAMP PRODUCING ULTRAVIOLET ENERGY SHIELDED FROM EYESIGHT, AN INDUCTIVE BALLAST HAVING A FIRST WINDING ELECTRICALLY CONNECTED IN SERIES WITH THE LAMP AND A SECOND WINDING INDUCTIVELY COUPLED THERETO, A NORMALLY NON-CONDUCTING SWITCH MEANS SHUNTING SAID LAMP RESPONSIVE TO ELECTRICAL CURRENT CHANGES IN SAID FIRST WINDING FOR CONDUCTING CURRENT THROUGH SAID FIRST WINDING UPON LAMP FAILURE, AND AN ELECTRICAL DEVICE CONNECTED IN SERIES WITH SAID SECOND WINDING. 